What's up? I'm new to the Altima forum. I was just like you, lol... I have a 2011 2.5 SL and I instaled a Sony DVD, NAV unit and I'm looking to upgrade the door and rear deck speakers. I see people are talking about maybe needing to cut holes out to make speakers fit?? I also wanted to put speakers in the back doors. It's empty but I see the case for them. Do you know if it's pre-wired?? Last, people say the rear aftermarket speakers have low bass when you replace them, why is that? Thanks for your help..